TIVAPs provide secure and reliable central venous access for intermittent long-term infusion therapies[4, 8], which are convenient for cancer patients to ensure the safe delivery of chemotherapeutic drugs, the transfusion of blood products and the performance of laboratory tests. When compared with externally tunnelled catheters, TIVAPs are particularly desirable for children undergoing long-term chemotherapy, as the catheters require less maintenance and do not limit daily activities, such as taking a bath. More importantly, TIVAPs are invisible from outside view and have little risk of accidentally being pulled out of the tunnelled catheter, which is more acceptable by the parents.
Despite these various advantages, certain complications that are associated with the implantation procedure or the long-term use of the TIVAP may occur. These complications can be divided into 3 main categories: procedural complications (such as haemothorax, pneumothorax, cardiac arrhythmia, injury of the brachial plexus and catheter malposition), early complications (occurring before the first chemotherapy application, such as pocket haematoma and fibrin formation) and late complications (occurring after the first chemotherapy application, such as thrombosis, infection, “pinch off” syndrome, catheter rupture, embolization, extravasation and catheter migration)[4, 11–13]. Among all of these reported complications, catheter migration is rarely seen but is regarded as being a potentially severe condition, which can likely lead to TIVAP replacement or removal. To the best of our knowledge, this is the first case in which the migration of the TIVAP catheter tip to the right thoracic cavity occurred in a child as an early complication. In the present case, catheter migration to the thoracic cavity was detected by the aspiration of slightly bloody fluid without obstruction at 2 days after implantation as an accidental finding and was subsequently confirmed via ultrasound and fluoroscopy. It is clinically asymptomatic and likely to be carelessly ignored, which may result in more severe events if chemotherapeutic drugs are injected into the thoracic cavity.
Several plausible reasons are considered to have contributed to catheter migration in this child. First, the lower puncture point on the neck and the more vertical pathway may have led to the condition in which the guidewire inadvertently went through the thoracic cavity before entering into the IJV or superior vena cava. Although the puncture procedure was performed by a senior anaesthetist under ultrasonographic guidance, which has been demonstrated to significantly reduce the complication rate[14–16], a suspected vascular puncture still occurred due to imprudent surgical manoeuvres as, in retrospect, the introducer needle was placed under the skin for a relatively long pathway before entering into the lumen. The special body constitutions of children, such as a short neck, may possibly contribute to the improper selection of the puncture point and pathway angle, which may account for catheter migration into the thoracic cavity. In addition, the type of catheter, the entry point into the IJV and the 'out-of-plane' puncture approach are also associated with catheter migration after TIVAP insertion via the IJV. The standardized TIVAP implant procedure, extensive insertion experience and adversarial repeated puncture attempts are reported to reduce the complications of catheter insertions[18, 19]. Second, undue pressures developed by bolus flushing and peristaltic pumps may also increase the risk of catheter migration. Therefore, the flushing of the catheter should be performed in a gentle manner[20, 21], and the limited speed of the peristaltic pump may aid in the prevention of catheter migration. Third, excessive movement and frequently increased intrathoracic pressure (as a result of the active lifestyle and lachrymose characteristics of children) may also potentially contribute to migration. In addition, the risk of catheter tip migration has been reported to be associated with the short catheter length inserted into the body and the shallow tip location.
When considering the various early complications of TIVAP implantation, delayed usage of catheters with an 8-day interval is advised. Although periprocedural antibiotic use is controversial and has not been verified to be associated with long-term infection rates, we suggest the routine application of prophylactic antibiotics through the TIVAP for 48 hours, which may decrease the early infection rate and aid in the detection of early complications. In addition, regular follow-ups with chest radiography and flushing with heparinized saline each time before the application of the TIVAP device are indispensable. If unobstructed aspiration of slightly bloody fluid is detected before the flushing with heparinized saline, a chest radiograph should be immediately performed to investigate the possibility of catheter migration into the thoracic cavity, as the early detection of the migration and reimplantation of the TIVAP device may aid in the prevention of further complications. It is sometimes difficult to identify the accurate position of the catheter tip via X-ray imaging, and two feasible methods may aid in probing whether the catheter tip is in the thoracic cavity. The first method is to confirm the occurrence of a hydrothorax via chest radiography after the injection of saline solution through the TIVAP. The second method is to observe whether there are any microvesicles in the right atrium via ultrasound during the bolus injection of saline solution through the TIVAP.